Dear Answerer!
What are the formulas for calculating the magnetic force?How could we maintain the force of a permanent magnet?For lifting and holing up a weight by a permanent magnet, what are the formulas and sequences? If we need to have two permanent magnet with the same physical dimension but different magnetic forces what shall we do? Please lead me for the perfect sources and possible solved examples.
Thank you very much
sight2121

Here is a site on how to store magnets so that they do not become easily weaker with time.

Also, have a look at wikipedia. There are interesting facts in there.

http://en.wikipedia.org/wiki/Magnetic_field

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